Such a support fabric is known, for example, from EP-B1-0 024 777. In this known support fabric, all the straight warp yarns are formed from polyester or from polyamide, polypropylene, polyethylene or aramids. The reference does not suggest, and virtually excludes, a support fabric which is a composite having a portion of the straight warp yarns made of polyester and another portion of the straight warp yarns made of another polymer as it is directed to a support fabric having great strength for use in construction.
It is true that this known support fabric is highly suitable for the purposes mentioned in European Patent Specification EP-B1-0 024 777, but its suitability for supporting, in particular, chemically aggressive bulk goods still leaves a great deal to be desired. For instance, a support fabric for a waste disposal site is required to last longer than 10 years. This requirement is frequently beyond the limited chemical resistance of polyester. On the other hand, the long term low breaking extension of straight warp yarns attained with polyester in particular result in a high modulus that, combined with minimal creep, are properties that make polyester particularly suitable for support fabrics of the kind in question here.